Process for dyeing leather



Patented Oct. 26, 1937 PROCESS FOR DYEING LEATHER Joseph Gyr, Basel, Switzerland, assignor to Society of Chemical Industry in Basic, Basel, Switzerland, a Swiss firm No Drawing. Application December 8, 1933, Se-

rial No. 701,567. In Switzerland December 21,

6 Claims.

According to this invention leather is dyed in fast colors and the dyestufl's used are complex copper compounds of azo-dyestufis of the general formula R1N=NRzN=NRa wherein R1 is the radical of a diazo-compound containing lake-forming groups, Re is a phenyl radical containing at least two hydroxyl-groups,

and Re is the radical of a diazo-azo-compound, the V diazo-group in which belongs to a .monoarylradical.

For making azo-dyestufls of the above general formula, the copper compounds of which are to be used in this, invention, there come into consideration as diazo-compounds containing lakeforming groups (R1) the diazo-compounds of the benzene and naphthalene series, which contain in ortho-position to the diazo-group a hydroxyl-, carboxylor alkoxy group or which contain a salicylic acid-grouping. Such diazocompounds comprise, for example, the diazocompounds of the ortho-aminophenols, orthoaminonaphthols, ortho-aminoalkoxybenzenes, ortho-aminoalkoxvnaphthaienes, anthranilic acids, ortho-aminonaphthalene-carboxylic acids, amino-salicylic acids, and the sulfonic acids and nitro-', alkyland halogen-substitution products of these compounds. As compounds which represent a phenyl-radical containing at least two hydroxyl-groups (R2) there come into consideration, for example, 1:3-dihydroxybenzene, 1:3- dihydroxybenzenei-carboxylic acid, 1:3-dihydroxybenzene--carboxylic acid, 1:2:3-trihydroxybenzene-Ea-carboxylic acid, as well as sulfonic acids and nitro-, alkyland halogen-substitution products thereof, so far as these are suitable for coupling twice. Finally, for making azo-dyestufis of the above general formula there may be used as diazoazo-compounds the diazogroup of which belongs to a monoaryl radical (R3), such as, for example, a monophenylor mononaphthyl-radical, for instance 4-diazoazobenzene-4'-sulfonic acid, 3:2'-dimethyl-4-diazoazobenzene-4'-sulfonic acid, 4'-hydroxy-4-diazothalene-6-(7l-sulfonic acid and 4-nitro-1-aminobenzene-azo-1-diazonaphthalene-6-sulfonic acid, and further substitution products of these compounds, such as, for example, halogen-substitution products.

In the manufacture of the azo-dyestufis of the above general formula by action of the diazocompounds on the coupling components,- the coupling may follow in any order and, in accordance with the selected order and the nature of the diazo-compound, may be caused to occur in neutral, acid or alkaline medium, for instance a medium containing sodium carbonate, sodium bicarbonate, alkaline earth, caustic alkali, ammonia, pyridine, acetic acid or hydrochloric acid. So also, the copper compounds of the dyestufls thus obtained may be made by treatment of the dyestuffs with various agents that yield copper, for instance copper sulfate, copper chloride, tetrammine-cupric sulfate or copper acetate, if desired in the presence of organic bases, such as pyridine. The agent yielding copper may be brought into action upon the monoazo-dyestuff containing lake-forming groups or on a 'flnished polyazo-dyestufl. Furthermore, the dyestufi may be treated with the agent yielding copper, either in the dye-bath or in the course of the manufacture of the dyestufl. The cupriferous azo-dyestufis of this invention dye leather, tanned in any manner, uniform brown to brown-velvet to black-brown tints. The dyeings are very fast to acid and alkali and excellently fast to light.

The following examples illustrate the invention Example 1 Neutralized chrome leather (box-willow calf, chrome sides, glazed kid, full chrome sheep) are tumbled in the cask in 3-4 times their weight of water at 60 C. During the rotation there is SOaH azobenzene-3'-carboxylic acid, 4-nitro-1-aminobenzene-azol-diazo-B-hydroXynaphthalene-3 6 disulfonic acid, 4-diazo-3-methoiw-azobenzene- 3'-sulfonic acid, aminobenzene-azo-l-diazonaph- After 40 minutes the liquor is run oil. from the leather, which is then stufled as usual.

The leather thus dyed has a very full, dull brown color, which is very fast.

Example 2 Well fulled vegetable-tanned sheep or goat skins are dyed in neutral condition as described in Example 1. At the end of the dyeing operation formic acid amounting to half the weight of the dyestuff used is added, whereupon dyeing is The leather thus dyed has the same color as the leather dyed as described in Example 1.

It is also possible to dye the neutral leather by a brushing operation using cold liquor.

The following table comprises some of the dyestufl's applicable as parent materials for the production of the copper compounds for use in the continued for 10 to 15 minutes. The goods are invention, the color produced with aid of the copthen rinsed. per compounds being given:-

I. Dim-component Coupling-component II. Diam-mmponent z g a x (B1) (Ba) (Ba) pound 1 2-gmino-1-hydroxybenune-4-sullonic acid--- 1:3-dihydroxybenune. 4-aminoazobenuno-fl-sulionic acid Reddish-bmwn. 2 do Dehydtothio-toluidlne-sullonic acid-azo-l- Do.

amino-8'hydroxynaphthalano-3 Misulionic acid. 3 dc 4-nitro-1-aminobenuno-uo-l-amlno-8-hy- Do.

hthalenedzo-disulionic acid. 4 do do -hydroxyszobenune-3'-carbox- Do.

5 2-an1inio-4:6-dinitro-1-hydroxybonune..--; do.. ai ga es? 4 aminoazobcnuno -4' Do.

c 6 2-amino-1-hydroxybenzene-4-su1lonlcuid... do. mlno-a-methoxy-azobenzene-r-sullonic Do. 1 o-amino -4- sullo -1-hydroxybenzene -2- cardo Z:2'-dimethyI-4-aminoambonme-4'-sxfl- Do.

boxylic acid. ionic acid. 8 Hmino-l-hydroxybenzeno-ksulfonic acid... do Aminobenuno-m -1-aminonaphthalene- Violet-brown.

6-(7)-suifonic acid. 9 do do 4-nitro-l-aminobenzono-uo-1-aminonaph- Do.

thalene-o-sullonic acid. l0 4:6-dinitro-2-amino-l-hydroxybanzene. 1:3-dihydroxybcn- 4-amino-4-hydroxyazobenunc-3'-car- Brown.

zone-Q-carboxylio boxylic acid. acid.

The formulas of the azo-dyestufls of the above table are the following:-

03 HO 0H OH HO OH OH 2. N N N=N S OH;

N ion on! now OH HO OH 8. N-N N- N=N-ONO| on! H018 50m 01! K0 0H 4. N-N N=NON=NQOH OOH OH HO 0H 1 5. NO N-N Cal 011 no on v N=NON=NQ sofli on V Din 08H N0 N=N on 10.

What I claim is:-

1. The process of dyeing leather, comprising using the complex copper compounds of azo-dyestufls of the general formula on no on Q =N N=N-Ra wherein R3 is the radical of a diazoazo-cgmpound, in which the diazo-group belongs to a monophenyl-radical, which copper compounds are brown to dark colored powders dyeing leather fast brown to brown-violet to black-brown tints.

2. The process of dyeing leather, comprising using the complex copper compound of the amdyestufl of the formula which product is a brown powder dyeing leather fast brown tints.

3. The process of dyeing leather, comprising using" the complex copper compounds of a20- dyestufis of the general formula HO OH R1-N=N N=N-11:

wherein R1 is the radical of an ortho-diazophenol containing an SOaH group in para. position to the OH group, and Rs is the radical of a diazoazocompound in which the diazo group belongs to monoaryl radical. 1

4. The complex copper compounds of the trisazo-dyestuiis of the general formula HO OH wherein R1 is the radical of an ortho-diazophenol containing an SOaH group in position to the OH group, and Re is the radical of a diazoazocompound in which the diazo' group belongs to a of dyeing leather brownish tints.

5. The complex copper compounds of the trlsazodyestufis of the general formula OH HO OH OaH 2,067,276 monoaryl radical, said compounds being capable phenyl radical, said compounds being capable of dyeing leather brownish tints.

6. The complex copper compound of the lamazodyestufl 01' the formula OH HO 15 wherein Ra is the radical or a diazoazo-compound which compound dyes leather brown.

in which the diazo group belongs to a monoe J OSEPH- GYR. 

